Modulated phase of liquid crystals: Covariant elasticity in the context of soft, achiral smectic-C materials

Abstract

Ginzburg-Landau–de Gennes-type covariant theories are extensively used in connection with twist grain boundary phases of chiral smectogens. We analyze the stability conditions for the linear, covariant elasticity theory of smectic-C liquid crystals in the context of achiral materials, and predict an equilibrium modulated structure with an oblique wave vector. We suggest that a previous experimental observation of stripes in smectic-C is consistent with the predicted structure.